Andrews, Lawrence and Will: “The 6 elements of Orofacial Harmony”, live presentation at ORTO 2004SPO in Sao Paulo, Brasil, October 9, 2004

Abstract by McGann

There were about 500 attending this 4-hour lecture in Sao Paulo, which was a major number of the approximately 3000 orthodontists attending, especially considering there were 10 other lectures in local languages at the same time period. Translation headsets with the option of Portugese or Spanish were provided and about 95% attending were using the headsets.

Larry Andrews, the father, started the presentation, saying that this could only be an overview of the 12 days of courses offered with the total content. If anyone was interested after this presentation, then take the course.

The Andrews (research) foundation is now onto the 6-elements of facial harmony, of which one is the 6 Keys to occlusion previously introduced in 1972. The Straight Wire Appliance (SWA) is a way to get to the 6-keys to occlusion, whereas the 6 elements are “standards”, considered as “optimal”.

Larry Andrews feels that orthodontists should be experts in occlusion and function, showing the rest of the dental profession that they know how teeth should function, not being outdone by the gnathologists. To obtain this level of understanding, mounted casts for every patient is needed, which of course they have just developed a new “disposable” articulator for each patient that only costs $30 per case if purchased in quantity. He does NOT feel that orthodontics deserves to be a specialty with the current state of standards and the inability to communicate the final goals of treatment. The Angle classification does NOT sufficiently classify a case.

The 6 elements are:

  1. Arch shape and Length: quantified so there is no controversy of extraction vs. non-extraction
  2. Antero-posterior jaw positions
  3. Buccal Lingual position of the jaws
  4. superior-inferior Jaw Position
  5. Pogonion prominence
  6. 6 keys of occlusion

The 6-keys were for dental harmony, the 6-elements for dentofacial harmony, looking as good as a patient can look. The 6-element treatment goal frequently involves orthognathic surgery, which is often an outpatient procedure in San Diego. Larry has practiced the 6-elements now for 15 years, and is now happy enough with the results to start work on his next book on this subject. If there is no surgery consent, then you get as close as possible with orthodontics only.

He then showed before and after photos (right profile with smile and right occlusion of the teeth) of 20 patients to illustrate the 6-elements. Almost all were orthodontic alignment with orthognathic surgery. (so who accomplished the end result? Surgeon or Andrews? Many heads were shaking in the audience as orthognathic surgery is rare in Brasil, being too expensive and lacking in skilled surgeons).

The arch shape can be uniquely identified for each patient, being named by Andrews the “WALA ridge” after the initials of Will Andrews and Larry Andrews, and pronounced similar to “Voila” in French. This is the mucogingival junction essentially on the buccal of the teeth, and generally represents the position of the buccal cortical bone. [remember that McGann found the lingual shadow, which represents the shape of the mandible]. Andrews hand contours each archwire to this WALA ridge shape and size. Nothing preformed has been made.

Andrews has made a plastic template with the occlusal plane and the upper incisor at +7 degrees to this plane and the lower incisor –1 degree to this plane (as in the torques found in the 120 normal cases studied to make the SWA). Andrews takes a ceph tracing, then draws in the “correct” incisor position by this template where the root is centered in the maxillary alveolus and mandibular symphysis (over basal bone). [this is the same as the concept of “decompensation” before orthognathic surgery]. If there is still antero-posterior discrepancies such as overjet, then surgery is necessary to make the correction after the orthodontic decompensation to this ideal position. The roots are centered over basal bone and the crowns to the 6-keys. He does NOT use cephalometric measurements, NOR does he look at the molar relationship. He wants the molars to be centered in the bone (buccal-lingual), which is not seen on the lateral ceph.

He commented on expansion in kids, which can expand the alveolus, but of course does not expand the basal bone. You would not want to do anything on kids that you would not do on adults, says Andrews.

Orthodontics needs a reference where to place the upper incisor teeth for best facial harmony. The occlusal plane and FA points for bracket positioning for the 6 keys are universal. Crowns are then inclined so they function gnathologically.

Element 1 conclusion: The staff forms the archforms to the WALA ridge, which is wider than FA point. The SWA thus forms the teeth to the WALA ridge, satisfying Element 1.

McGann comments on Element 1: I agree with the concept of the archwires being formed for each case, according to an individual reference, in this case the WALA ridge. But, this means that ALL patients will receive arch shape and size that generally “maintains” the original arch shape and size, not leaving the open thinking of expansion, constriction, and non-coordinated archwires in selected treatment plans. At least this is not treating patients to the “normal ideal” of the 120 studied patients, adding an element of individualization to the archwires. Practically, I cannot see forming archforms in this way for each patient, previously rejected by the profession after forming archwires for every patient in the diagnostic arch concept (not much different, except that Andrews is looking at the bone, where diagnostic arch looks at teeth). Andrews says that teeth are everywhere, which I completely agree with. The IP system of lingual shadow and preformed archwires, considering each patient AND TREATMENT, seems to be a much more practical answer.

Will Andrews

The son was in charge of presenting Elements 2,3,4,5. There “never will be” a place where the position is correct. In Element 2, the teeth in element 1 are placed over the jaws, so now where are the jaws? A reference line is needed. Society determines the reference line, and Andrews relates this to the forehead since this is the most consistent part of the head. They accumulated 1000 photos from magazines where the forehead and upper teeth were visible to determine acceptability in society. The frontal plane of the head is then determined by a midpoint between Gabella to the hairline (Trichion) and a vertical line is made by “judgment” of the clinician from this midpoint of the forehead. The upper incisors are then related to this reference line. A second line is drawn parallel to this frontal plane from Glabella, forming a “range” of acceptability for upper incisor positioning.

They found that rarely did the upper incisors fall forward of this glabella (vertical) line, and almost never behind the FFA (center of forehead point) vertical line. Racial diversity did not matter, neither did male vs. female, nor age differences (no need for growth forecast). The lines are drawn by “estimation”. The Frankfurt horizontal plane is discounted as a reliable reference as are all other cephalometric measurements. They show cast mountings where the Frankfurt horizontal gave an erroneous impression of the occlusal plane. Throw out the ceph they say.

He discussed the nasolabial angle and E plane, showing that there was not necessarily any relationship of the lips to the underlying teeth. Some races have thicker lips, others thinner soft tissue in front of the teeth.

Finding the reference line involves first finding the FAA (frontal facial axis point) of the forehead. There are 3 shapes of foreheads, with a straight forehead having FAA between Trichion and Glabella. The “rounded” forehead gets another point called “superion” which is at the point on the curve where the forehead becomes clinically insignificant to the face, with FAA between superion and Glabella. The angular forehead, which is straight, then curves near the hairline, gets superion placed on the convexity of this curve, then FAA half way between superion and glabella.

The doc then makes an estimate of where the teeth fall relative to a vertical to the face from this point, indicating “2mm forward” or “2mm back” of this reference line. The more inclined the forehead, starting at a 7 degree angle, the teeth can be 0.5mm more forward for every 1 degree of extra inclination, but never beyond glabella.

Inferion point is the point on the upper incisor, in front or back of the frontal plane of the head. They then take a lateral ceph x-ray, placing barium paste on the forehead at trichion, FAA and Glabella points, so they can see these on the ceph. The “clinical judgement” is then transferred to the lateral ceph record, and the treatment objective of incisor retraction/protraction decided.

They did studies of the “judgement” for frontal plane determination from photos and determined they were 1-2mm Standard Deviation (I remember 1SD to be 67%ile, so this is not too impressive to me, but they of course did not explain standard deviation).

Element 3: Buccal lingual position of the jaws

This relates to the teeth within the buccal-lingual width of the jaws. The correct inclination of molars shold be –30 degrees for lower 6s and –7 for upper 6s, measured at the buccal surface. 5 degrees equals 1mm of teeth moved by tipping in maxillary expansion by round wires. Andrews looks at the lower molars to determine if they need to be uprighted to get to the proper inclination, then determines the expansion needed. This of course leads into lots of surgical expansion and Rapid expansion (50% skeletal is what I remember from RPE, but not factored into the calculation).

Element 4:

Hairline to Glabella should be 1/3 proportion of the face, same with glabella to subnasale, same with subnasale to menton. In the posterior, external auditory meatus (ear on face) to soft tissue gonion should be the same 1/3 proportions. This seems to help them in surgical planning.

Element 5: lower incisor to pogonion.

You do not want pogonion to be in front of the lower incisor. 10+ patients are shown, all had surgery to meet this criteria.

Larry Andrews returns

6 keys is the last element. There are tools and rules, which the SWA is used to attain. He still recommends the several prescriptions for extraction brackets, which emphasize tip and rotation when extraction space is closed.

He then described the course they offer. 3 days for diagnosis, 3 days for cast mounting and splint therapy, TMD is solved before ortho diagnosis with the true diagnosis in centric relation.

It is inadequate to use one appliance for all patients. Occlusofacial articulator should be used for every patient to treat to Centric Relation.

By the time the 6 keys started, there were approximately 50% remaining of the original audience. By the end of the presentation, about 90% had been lost. Questions were asked.

  1. 014N is used only for the first few months since not possible to contour to the WALA ridge, then custom bent stainless steel wires after this.
  2. No VTO with growth forecast since the proportions remain the same.

McGann comments:

This is the age old habit of trying to treat everyone to a standard, that of the original 120 ideal patients without previous ortho. A slight attempt at individualization is made with the archwires and 11 extraction bracket sets, but falls way short of individual patient diagnosis, treatment planning, and treatment in my opinion. Surgery is heavily relied upon to get everyone to the “ideal”, which is very dangerous. We can never fit everyone to any standard, but instead must treat each individual on its own merits.